The new James Bond movie, Skyfall, which came out in the U.S. this weekend, is pretty clearly a James Bond movie. It’s got the girls, the locations, the suits, the martinis, the villain. But there’s one way in which Skyfall is different from every one of the 22 other Bond movies made by Eon Productions — and if you’ve already seen the movie, because this is sort of a spoiler, even though we’re not going to spoil the two really huge twists in the movie even in a post called “Spoiler Alert,” and if you’ve seen the movie then you know what we mean — read on to hear an explanation of that choice straight from the director’s mouth.

The difference in question is the gun-barrel sequence, the series of shots that has appeared at the beginning of every movie since Sean Connery first picked up his license to kill. Bond walks into the frame from the right. We see him through the barrel of a gun. He turns. He shoots. Red oozes from the top of the frame. It means the movie is, after an introductory scene, really starting. But if you’ve seen Skyfall, you know that the introductory scene is the whole movie — the gun-barrel sequence appears at the very end.

So what deep meaning might that choice hold? We asked director Sam Mendes:

I was curious about the decision to put the gun barrel at the end of the movie.It didn’t work at the beginning! Literally, that was what it was … It just didn’t look any good at the beginning. I wanted it at the beginning because I think that’s traditionally where it’s supposed to be. It’s almost the best part of some Bond movies; you’re like, Oh, great, it’s starting! That’s what it’s there for. But because the first shot of Bond in Istanbul is him walking toward the camera along that long corridor and he enters frame — and in the gun barrel he also enters frame — it felt like he was entering frame, shooting and then entering frame again. It doesn’t work. But then, given how the movie ends — the sense that Bond is back — it just felt right at the end. It felt thrilling. So we put it there.